Intraoperative monitoring in carotid surgery: transcranial Doppler versus somatosensory evoked potential method

Abstract

In the industrialised countries of the western world cerebrovascular insufficiency is the third most common disease affecting the general population following cardiac disease and cancer. Relevant statistics qualify cardiovascular disease as the leading cause of death in 40 % of cases. Of those affected, one-third die due to myocardial or cerebral infarction (6). The diagnosed new cases every year with disease of the supraaortic vessels increases exponentially with the patients’ gain in age: roughly 300 cases per 100000 in the age group 55 to 64 years and 1440 cases in the age category 75 to 84 years. Above 85 years a prevalence of 2000 per 100000 has been documented (2, 5, 9). The expected stroke rate in the population therefore correspondingly rises with the currently increasing mean population age of western societies. Two-thirds of the patients who survive a stroke are handicapped by the incident, and 10 % of these require full-time care (12). Half of these patients survive another 5 years, and one-third of these require prolonged rehabilitation in specially equipped centres. The cost of caring for these patients in the United States is estimated to lie at 9 Million US $ per year. Roughly 75 % of the extracranial arterial lesions can be reconstructed in vascular surgical procedures in order to achieve an adequate cerebrovascular circulation. The cost for this type of treatment in the states was calculated to be 1.25 Million US $ compared to the above mentioned figures (8).